For those who plan their vacations or -- laws or theme parks and might bring a queasy shocked to realize an alarming number of Americans plan their vacations. -- on the flesh of children. Every day young girls are bought and sold in developing countries. Where the grim economics provide -- cheap and vast selection. For the average sex tourists and after a six month investigation we found that Americans are not only buying some are also selling. But little -- -- know the authorities are also watching even over there tonight Nightline producer Alex water field. -- ABC's Alex marked for tickets to the Philippines and take us inside. The right. Tonight in the -- long part of the Philippines. Are there Benjamin isn't a good move yeah. -- laughing drinking overruling the girls dancing on stage of this car. Which he says he owns this is your life. Benjamin is a 49 year old American suspected of having sex with underage girls. And selling sex out of this bar called crowbar. And as he drinks Benjamin had no idea at that very moment the first started didn't improve our. Filipino and American authorities are just a few miles away. -- a radio will bring his world. Crashing down. This is the story of mark their Benjamin. We traveled to Subic Bay beautiful part of the western Philippines Benjamin has been living for 25 years. But our journey went deeper past Benjamin into the dark and disturbing world of underage prostitution. Discovering how all too easy it is. To buy sex with underage girls how old -- you. The Philippines quietly emerged as the top destination for Americans not just looking to have sex -- -- -- -- there -- cared. But to sell sex as well. On the Americans want to come here because they perceive it's easier to operate here. -- -- -- in the United States and we're happy to remind them that they are they are sadly mistaken Eric McLaughlin is a special. Agent with the immigration and customs enforcement agency investigating Americans who may be committing crimes here in the Philippines. For the Benjamin case he recently teamed up with a local nonprofit organization called Prado. -- which has been gathering evidence against Benjamin for months it's my job as a US law enforcement investigator to determine if those allegations are accurate -- thereafter we will pursue them to the ends of the earth to make today held accountable. We want to meet Benjamin. And see for ourselves what's going on inside that -- red light according to producer Alex water field and -- put on these tiny hidden cameras and looked like shirt buttons. We hop on the local GP head down to a rundown part of town conventions bar. Don't know what to expect. -- around a dozen young women are milling around. Looting this one's listening. Princess is one of the most popular girls in the bar. Just sixteen years old. And it's not long before princess and another girl. Our offer to -- 15100 pesos just under forty dollars. -- Lucy is what's called a moment someone -- manages the girls. We declined her offer but she called Benjamin to come meet us. What are they need. The bargaining. Within minutes the six foot six Texan tells us about his sex life and his business. -- -- -- A former waitress had written to his wife in California on FaceBook. Which leads to this shocking and frank statement. -- -- -- -- -- -- -- -- -- -- -- girls from this high school. Oblivious to our hidden cameras. Benjamin tells us he has a sixteen year old girlfriend lives in -- house -- back. And after texting her to come over. She walks in. She's so young we're -- her face to protect her identity. Benjamin's declarations so stunning. Following morning we felt we had to alert special agent Eric McLaughlin. But he says building a case against Benjamin requires more evidence so this guy saying on tape I've had sex with underage girls repeatedly. That's not enough to arrest and no it's it's a very strong indication but we have to as investigators we have to prove -- actual acts occurred to me just saying that that's not enough. The key might be this eighteen year old girl -- -- -- until December she worked at Benjamin's -- Today Marysol has come to the greatest center a nonprofit that began tracking Benjamin and identifies and photos for girls who worked there. She says are underage including the one we met. -- why did you decide to tell your story what what do you want. Diana I felt hopeless working in the bar she says that my friends especially the miners feel the same way. I wanted to tell my story and to save them. Benjamin isn't the only American capitalizing on the demand. Many in this long string of bars and -- -- today. Are owned or managed by Americans. Many of them are military veterans. You guys like eight cars. I -- -- it's really -- it has -- just understand. Subic Bay was home to a US naval base for almost fifty years providing a boon to the prostitution industry very -- It's there. To see how easy it is for Americans to find underage girls. Visited the neighboring town of -- LS 45 minutes from Subic Bay and art Benjamin's bar. It takes less than half an hour before were approached by this woman. Offers us not just young girls but -- how many different groups. -- and I'm. -- one it's 30000 or 750 dollars. We'll talk about it and it'll come back and see you. Later that night we meet the woman and the girls near a busy intersection. -- they have. -- fifteen. And you. -- -- -- -- What -- are you wait a second so -- -- you look very nervous. Don't be scared and it's okay. -- -- -- -- -- -- She loves you. NYC asking -- to do this. Well that was incredibly disturbing -- -- both obviously so young and it was so easy for us. -- We said no thank you. Please come back for more -- The yeah. Authorities decide to make the final move on Arthur Benjamin -- -- Sit down but will they have enough evidence to arrest him.

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